Method of and apparatus for drying hops with rotary carrier



Aug. 25, L. s JESPERSON METHOD OF AND APPARATUS FOR DRYING HOPS WITH ROTARY CARRIER Filed July 5, 1968 .4 Sheets-Sheet 1 H Q I AAINVENTOR LESLSE S. JESPERSDN ATTORNEY Aug. 25, 1970 L. s. JESPERSON 3,525,161

METHOD OF AND APPARATUS FOR DRYING HOPS WITH ROTARY CARRIER Filed July 5, 1968 .4 Sheets-Sheet 2 Aug. 25, 1970 JESPERSON 3,525,161

METHOD OF AND APPARATUS FOR DRYING HOPS WITH ROTARY CARRIER Filed July 5, 1968 v4 Sheets-Sheet 3 LESLIE 8.. JESPERSON 3 BY 6.? 82 ATTORNEY Aug. 25, 1970 L. s. JESPERSON 3,525,161

METHOD OF AND APPARATUS FOR DRYING HOPS WITH RbTARY CARRIER Filed July 5, 1968 .4 Sheets-Sheet 4 INVENTOR LESLIE s. JESPERSON ATTORNEY United States Patent 3,525,161 METHOD OF AND APPARATUS FOR DRYING HOPS WITH ROTARY CARRIER Leslie S. Jesperson, Rte. 1, Box 361-A, Selah, Wash. 98942 Filed July 3, 1968, Ser. No. 742,284 Int. Cl. F26b 5/08 US. Cl. 34-8 30 Claims ABSTRACT OF THE DISCLOSURE Hops are delivered from a harvester by a conveyor to a delivery mechanism which is capable of traversing a rotary drying kiln repeatedly and to lay down upon the rotating floor of the kiln layers of hops having an even density. Warm drying air circulates upwardly through the foraminous floor to dry the complete batch, after which drying the entire batch is discharged from the floor by centrifugal force and delivered to an outlet conveyor at a lower elevation. The floor of the kiln moves relative to the wall of the kiln to facilitate the centrifugal discharge.

BACKGROUND OF THE INVENTION The prior art accepted method of drying hops involves the use of a stationary kiln having one or more approximately square compartments with stationary floors about ten feet above ground level. Each compartment may measure about thirty-six feet along a side. The floor generally consists of slats spaced several inches apart over which metal screen or foraminous fabric is stretched. The hops are spread on this floor to a depth of about thirtysix inches with as much uniformity of density as possible by a laborer using a fork. Hot air is then forced upwardly by fans below the foraminous floor and circulated through the hops in the kiln. After approximately eleven hours, the drying of a batch of hops will be complete. During the drying period, the hops are checked periodically by a laborer walking through them and feeling various areas to determine moisture content. Due to variations in density and concentration of the hops, some portions of the batch dry faster than others and it is very difficult to secure the desired uniform moisture content. When the hops are thought to be sufficiently dried, the heat is discontinued and a door at one end of the compartment is opened and through this door laborers using scoops push the hops from the compartment onto a conveyor which carries the hops to a cooling room where they are later baled. Quite obviously, this is a cumbersome, inconvenient and inefficient method and the process is very uncomfortable for the workers and very time consuming and expensive.

The present invention employs an apparatus for the practice of a new method of drying hops which overcomes completely the inadequacies of the prior art and eliminates most of the manual labor and lost time and also results in the attainment of a very uniform moisture content, which is important. The hops are conveyed into the apparatus and are deposited in uniform density layers on a rotating foraminous floor through which the drying air is directed. With the invention method, the cooling time period essential in the prior art before the kiln can be unloaded is entirely eliminated and the rotary kiln unloads the entire batch of hops automatically after sulficient drying and deposits them on another conveyor for carrying to the desired point without further labor. This point of destination will normally be the cooling room. The invention offers a number of specific advantages over existing methods in addition to lower costs, including the following:

(1) Heat can be applied as soon as one layer of hops 3,525,151 Patented Aug. 25, 1970 is laid, thus saving drying time and elimination of compartmented kilns.

(2) Many times, because of harvesting machine failure or other causes, it is necessary to dry only a portion of a batch. The invention eliminates the necessity for spreading burlap over the unused part of the kiln compartment so that heat does not escape therefrom.

(3) With the invention, there is a better mixing of hops so that rained-on hops or wilted hops will not be disposed at one point in the batch but distributed uniformly, thus lessening variants in drying.

(4) Construction of the apparatus is cheaper and the apparatus is more readily prefabricated.

(5) Shattering of dry hops caused by manual pushing of the hops from the kiln and walking on them is greatly reduced or eliminated.

(6) Much time is saved in the unloading of hops from the drying kiln since the waiting time period for cooling prior to manual unloading is eliminated.

(7) The necessity for skilled labor to lay a kiln of hops is eliminated SUMMARY OF THE INVENTION The invention apparatus embodies basically an elevated kiln chamber which is circular and open at its top with a revolving horizontal floor capable of being raised and lowered relative to the annular side wall of the chamber. In some cases, the side wall may be raised and lowered relative to the floor. A traversing mechanism delivers hops from a conveyor to the kiln by moving back and forth generally tangentially to an inner wall of the kiln chamber. The delivery mechanism includes a means to sense the depth of each layer of hops laid down on the revolving floor and the mechanism is automatically advanced another step across the kiln when the sensing device disengages the hops which have been laid down at one point. Successive layers of hops are laid evenly on the floor until a predetermined batch depth is achieved, at which time the delivery mechanism may move on to the next rotary kiln chamber in a multiple unit apparatus.

At this time, the floor of the filled compartment is lowered automatically and its speed or rotation is increased so that the complete batch of dried hops is discharged radially by centrifugal force from the foraminous floor into a conical funnel or hopper which delivers the hops to an outlet conveyor leading to the cooling room. The apparatus is further characterized by a unique water seal which prevents the escape of drying heat around the entire kiln. Since the discharge cone or hopper encloses the bottom of the kiln, the escape of heat at the bottom of the structure is also prevented. Various additional features and refinements to be described are also embodied in the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partly diagrammatic central vertical section through the hops drying apparatus employed in the practice of the method;

FIG. 2 is a horizontal section taken on line 22 of FIG. 1 and showing plural units or kiln chambers serviced by a single conveyor structure;

FIG. 3 is a vertical section taken on line 3--3 of FIG. 2;

FIG. 4 is a diagrammatic view illustrating the movement of the sensing means and delivery mechanism which lays the hops in even layers on the rotating floor;

FIG. 5 is an enlarged side elevation of the sensing means which facilitates the laying down of the hops in a level layer of uniform density;

FIG. 6 is an enlarged fragmentary vertical section taken on line 66 of FIG. 1;

FIG. 7 is a similar section taken on line 7-7 of FIG. 1;

FIG. 8 is an enlarged fragmentary vertical section through a water seal and showing the kiln floor in a lowered position for discharging hops;

FIG. 9 is a central vertical section through a modified form of the apparatus;

FIG. 10 is a horizontal section taken on line 1010 of FIG. 9; and

FIG. 11 is an enlarged fragmentary vertical section showing the raising of the annular wall of the kiln relative to a rotary floor which remains at a fixed elevation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings in detail, wherein like numerals designate like parts, FIGS. 1 to 8 inclusive show one preferred embodiment of the invention. In these figures, the numeral designates side vertical columns, spaced uniformly in two parallel rows, FIG. 2, to form the main supports for the hops drying apparatus consisting of several tangentially arranged kilns 21 as shown in FIG. 2. Any practical number of kilns may be provided in the installation, such as three or five kilns 21. FIG. 1 illustrates a single kiln 21 of the plural kiln installation and therefore to a great extent the detailed description of one kiln unit will serve to describe the entire installation or system.

Continuing to refer to FIGS. 1 through 8, a horizontal longitudinal belt conveyor 22 common to the several kilns 21 spans the tops thereof near corresponding sides of the kilns on one side of a common centerline through the several units. The conveyor 22 is bodily supported at the proper elevation on a series of horizontal arms 23 extending inwardly from the adjacent columns 20 and rigidly secured thereto. The arms 23 are braced by vertical members 24 which have their tops tied into a horizontal truss member 25 of a roof 26 which covers the entire installation.

The conveyor 22 includes spaced parallel bracket plates 27 upon which rollers 28 are mounted, said rollers forming a support bed for a preferably concave horizontal belt 29 which delivers the hops from a harvester to the drying apparatus in a continuous manner. The bracket plates 27 are firmly attached to the supporting arms 23.

Immediately outwardly of the bracket plates 27, V- shaped tracks 30 are carried by the arms 23 and serve to guide the wheels or rollers 31 of a carriage 32 having an inclined top section 33 including rollers 34. The carriage 32 engages beneath the flexible belt 29, as shown clearly in FIG. 3, and is adapted to travel on the rails 30 under the belt. The carriage 32 moves on the tracks 30 in response to the operation of a Windlass drive motor 34', FIG. 3, connected with a carriage drive cable 35 secured at 35 to the carriage 32, the drive cable also engaging a Windlass drum 36 near the remote end of the apparatus.

The motor 34 is suitably mounted near the opposite end of the apparatus so that the single cable 35 may propel the carriage over the several kilns making up the apparatus. Thus, the carriage moves relative to the belt 29, the belt having independent conventional drive means, not shown.

The inclined section of the belt 29 which is elevated by the carriage portion 33, FIG. 3, delivers hops from the conveyor 22 to the top of a delivery chute 37 having an inclined section 38 and an offset vertical lower delivery nozzle 39 directly over the kiln or drying chamber 21. The inclined portion of the belt 29, after engaging the uppermost guide roll 34, extends downwardly and reversely at 40, FIG. 3, and then engages another guide roller 41 on the bottom portion of the carriage 32 and then extends forwardly of the carriage and chute 37 on its regular horizontal path. The delivery chute 37 is suitably rigidly attached to the carriage 32, and travel therewith. Also associated with the delivery chute 37 and carriage is a vertically movable sensing bar 42 carrying a sensing element or finger 43 at its lower end. The details of this structure are clearly shown in FIG. 5 and the arrange- 4 ment constitutes a significant feature of the invention which will be described fully. The bar 42 and associated elements is bodily carried by the chute 37 and therefore moves with the carriage 32.

Each drying kiln 21 comprises a circular horizontal rotating floor 44 which is preferably slatted as by radial slats 45, said slats being covered with wire mesh 46 or other like foraminous material which will allow drying hot air to circulate upwardly through the rotating floor during the drying operation. As shown in FIG. 2, the outer ends of the elements may be attached to an annular structural member 47 constituting the peripheral edge of the floor and the floor is rendered sufiiciently rigid by the inclusion therein of radial truss members 48 Whose inner ends are rigidly attached to a vertical column 49 through which the fioor 44 is rotated in a horizontal plane and raised and lowered at required times.

In connection with the movements of the kiln floor 44, an overhead rotary drive motor 50 supported on the member 25 drives a sprocket chain 51, in turn engaging and driving a large sprocket gear 52, FIG. 6, keyed to a long keyway 53 in the top reduced extension 54 of column or shaft 49. The extension 54 is journaled for rotation in a bearing structure 55 suitably rigidly supported on the overhead structural framework. Through the sprocket gear 52, therefore, the column 49 and the entire floor 44 is rotated at the required times.

In order to lower the floor 44 to a discharge position for the hops after their drying is completed, a fluid containing cylinder 56 is rigidly supported on a bottom spider 57 including legs 58 and an external annular brace 59 for a large conical delivery chute 60 constituting the bottom enclosure for the kiln and whose purpose will be further discussed.

The cylinder 56, FIG. 7, receives telescopically a reduced extension 62 of column 49. A low friction thrust bearing 62 is provided between the bottom of the extension 62 and a piston cup 63' to ease the rotation of the column 49. The cylinder 56 may also have built into it a conventional air accumulator, not shown, to relieve expansion due to the heat of the drying process. When fluid enters the cylinder 56 from a line 63, the column 49 and floor 44 will be raised to the full up position shown in FIG. 1. When the floor 44 must be lowered to the hops discharging position shown in broken lines in FIG. 1, a certain amount of fluid is exhausted from the cylinder 56 by conventional valving means. When the column or shaft 49 moves downwardly at this time, the sprocket gear 52 is restrained from downward movement by a support bracket 64, FIG. 6, tied in with the overhead truss 25. Because of its sliding connection with the keyway 53, the sprocket gear 52 is capable of rotating shaft 49 and floor 44 in all vertically adjusted positions of the latter.

The central portion of the kiln floor 44 is formed by an imperforate barrier or plate 65 through which rising hot air cannot pass and an upstanding central annular wall 66 rises from the periphery of the plate 65 in spaced concentric relationship to the shaft 49. As will be described further, the delivery chute outlet 39 travels substantially tangent to the wall 66 and lays down the hops in the annular chamber between the central wall 66 and an outer annular imperforate wall 67 which rises above the floor 44 at the periphery thereof to an elevation just below the mouth of the discharge nozzle 39. The annular wall 67 is an entirely separate element from the floor 44 and the central wall 66 and when the floor structure including parts 46 and 66 move downwardly, the wall 67 will remain supported as depicted in FIG. 8 and its lower edge will be spaced from the floor 44 so that the hops may be discharged centrifugally from the slot or space 68 now existing between the lower edge of the wall 67 and the mesh surface 46 of the floor. As an incidental feature, a plurality of guide elements 69, FIG. 8, may be attached to the floor 44 at circumferentially spaced points to guide and center the wall 67 when the floor 44 is elevated.

In order to bodily support the wall 67 when the floor 44 is lowered to the discharge position, an external annular bafile 70 secured rigidly to the wall 67 is adapted to bottom on an internal plate 71 of a stationary surrounding wall 72 constituting an upper extension of the conical chute or wall 60, see FIG. 1. Another annular batfie 73 rises from the plate 71 somewhat inwardly of the baffle 70. When the floor 44 is lowered, FIG. 8, the annular plate 71 engages and supports the annular baflle 70 which then constitutes a hanger for the entire wall '67 which will be supported in spaced relation to the floor.

The elements 70, 71, 72 and 73 serve the dual purpose of providing an air tight liquid seal entirely around the kiln 21 near the top thereof so that the rising warm air cannot escape in the zone 74 between the walls 72 and 67. When the floor 44 is elevated, FIG. 1, it will be noted that the baffle 70 is spaced above the plate 71 and simply rotates with the wall 67 and floor 44 which is now supporting the weight of the wall 67. To maintain the mentioned liquid seal, water 75 is maintained in the annular space above the plate 71 to continually submerge a part of the baffie 70 at all times. The proper liquid level is maintained by a float valve means 76 operating within a small chamber 77 on the outer side of wall 72, there being a water inlet line 78, FIG. 2, leading to the chamber 77 and a communicating opening 79 between the chamber and the annular space within which the liquid seal is maintained at all times.

Hot air to dry the hops is supplied from a suitable source to all of the kilns 21 through a longitudinal duct 80 which extends along one side of the apparatus, FIGS. 2 and 1, somewhat below the top of conical wall 60. Branch ducts 81 lead from the main duct 80 through the conical wall 60 and this hot air being unable to escape from the conical wall 60 passes upwardly through the screening 46 to dry the hops in the annular space between the walls 66 and 67. Such hot air cannot pass through the liquid seal between the bafiles 70 and 73 and cannot pass the floor plate 65, which is imperforate.

A very important part of the invention is the ability of the apparatus to lay down on each rotating floor 44 even layers of hops up to a prescribed total depth within the confines of the wall 67, so that the total batch will have very uniform density. This is important in obtaining uniform drying. Also, the hops are well mixed throughout the drying chamber, that is, wilted or rained-on hops will not tend to be concentrated at any one point but distributed evenly throughout the entire batch.

In obtaining the above results, the sensing mechanism shown in FIG. plays an important role, now to be described. As the hops are being delivered to a particular kiln 21 by the conveyor belt 29, such hops are being dumped into the delivery chute 37 which is now stationed above a particular kiln 21. The floor 44 of this kiln is now rotating under influence of the motor 50 and the floor is in the full up position carrying the outer wall 67. The purpose of the chute 37 is to deposit the hops evently over the entire annular floor between the central wall 66 and the outer wall 67. The sensing finger 43 is initially at a low elevation, such as six inches above the floor screen 46. As the hops are discharged from the chute 37 to an elevation where they will engage and lift the finger 43, the finger being pivoted at 82 to the bottom of bar 42 will activate a switch 83 which in turn starts the carriage motor 34 and drives the carriage 32 and delivery chute 37 a sufficient distance toward the outer wall 67 to cause the finger 43 to disengage the hops on the rotating floor. It should be understood that the chute 37 operates from an initial position, as shown in FIG. 2, close to the center wall 66 outwardly in a generally radial path toward the outer wall 67. The chute 37 and carriage 32 then travel reversely back to the position shown in FIG. 2 but do not at any time move to the opposite side of center with respect to the kiln 21 depicted in FIG. 2. As will be further explained, hops are laid down or spread on the rotating floor while the carriage and chute are moving in both directions across the rotating floor.

Referring to FIGS. 3 and 4, it may be seen that the carriage 32 and chute 37 advance a step at a time horizontally with the sensing finger 43 and hops are being laid down in an even layer on the rotating screen 46 all the time as the carriage and chute move outwardly toward the wall 67 and then rearwardly toward the center of the kiln. The arrows in FIG. 4 depict the step-by-step movements of the carriage 32 and delivery chute 37 and the horizontal broken lines diagrammatically represent successive layers of hops being built up on the rotating floor in an even manner. In FIG. 3, the broken line representations of the bar 42 and sensing finger 43 represent the step-by-step movements of the carriage 32 under control of sensing finger 43.

The above process continues with the carriage and delivery chute traveling back and forth horizontally above the rotating floor of the kiln to build up the hops evenly thereon. The carriage 32 and delivery chute move a step forwardly or backwardly as the case may be'and the step movement is regulated or limited by the sensing finger 43 losing contact with the hops 0n the rotating floor. Additional hops from the conveyor are delivered to the floor through the chute and such additional hops on the rotating floor will again engage the finger 43 to operate switch 83 and start motor 34 to advance the carriage 32 a further step until the sensing finger 43 again loses contact with the hops. This process continues to cover the floor with even layers of hops as the delivery chute traverses back and forth on its generally radial path. In order to effect reversal of the carriage drive motor 34' and reversal of the delivery chute 37, a pair of limit switches and 85', FIGS. 3 and 4, are provided on the stationary wall 72 and on the stationary track structure 30 near the center of the kiln. Suitable extension elements 84 carried by the delivery chute 37 will engage and actuate the limit switches 85 and 85 to reverse the carriage drive motor 34' at the proper times. Upon each actuation of the switches 85 and 85', in addition to reversing the motor 34', a small motor 86 carried by the chute 37, FIG. 5, is activated and this small motor will cycle for one revolution only, causing a slotted link 87 to revolve, moving another link 88 and elevating a pawl 89 which is engaged with ratchet teeth 90 on the bar 42, said pawl moving within a slot 91 in the fixed guide structure 92 through which the bar 42 slides.

An upper holding pawl 93 trips over the teeth 90 as the bar 40 is raised and locks the bar at the next elevated position. This operation conditions the mechanism for the laying down on the rotating floor 44 of the next layer of hops while the delivery chute 37 is moving in either direction away from or toward the center of the kiln. This process is continued until the kiln is filled to a substantial level near the top of the circular wall 67, the topmost layer of hops being diagrammatically shown in FIG. 4. Ordinarily, a full batch of hops in the kiln will be approximately thirty-six inches deep, although this depth may vary somewhat.

When the kiln reaches a near full condition, the elevation of the bar 42 will be such that the top 94 of a trigger element 95 on the bar 42 will engage and operate a switch 96 to sound an audible alarm notifying the operator that it is time to move the delivery chute 37 and carriage along the tracks 30 to the proper starting position near the center of the next kiln 21. If the operator fails to respond for any reason, an extension 97 on the trigger 95 will operate a second switch 98 somewhat below the switch 96 and shut down the entire system, stopping the entry of hops into the kiln. The drying heat is applied through the floor 44 as soon as the first layer of hops is laid down on the floor. A trigger projection 99 on the upper end of bar 42 operates switch 96 and sounds the audible alarm after the first layer is laid down so that the operator will start the heat which enters the kiln through one of the branch ducts 81.

The lifting and holding pawls 89 and 93 may be equipped with electrical solenoids 100 or some like power means to effect retraction of these pawls so that the bar 42 may drop quickly to its down position after the carriage 32 has been shifted over to the next adjacent kiln 21. This is an optional feature and, if preferred, the two pawls may be manually retracted when the bar 42 is lowered.

It ordinarily takes two to three hours to fill up one kiln with hops by the invention method and thus considerable time is saved by commencing the heat flow as soon as the first layer is laid down on the rotating floor. At such time as the entire batch of hops is sufficiently dry for discharging from the kiln and movement to a cooling room, the rotation of the floor 44 is stopped. The heat and air inflow from the ducting 80-81 is now interrupted by closing suitable air gates, not shown. The floor is lowered by operation of the cylinder 56 to a position approximately as shown in FIG. 8. In this lowered position, substantially the entire batch of hops will be free of the side wall 67 and this side wall will be hanging from the batlle 70 as previously described in connection with FIG. 8. Rotation of the floor 44 is then commenced at a sulficiently increased rate to discharge all of the hops radially by centrifugal force from the edge of the rotating floor, whereupon the hops fall downwardly into the conical receiver 60 and delivers them through a bottom opening 101 onto another moving conveyor 102 which carries the hops to the cooling room.

The bottom opening 101 of conical receiver 60 has a retractable closure plate 103 operated by a hydraulic cylinder-piston unit 104, bracketed to any nearby structural member. The closure plate 103 is retracted to allow gravitation of the hops onto the conveyor 102 but is maintained in the closed position shown in FIG. 1 during the heating cycle so that hot air will not escape from the bottom of the kiln.

A suspended horizontal catwalk 105 spans the several kilns of the apparatus so that an inspector on this walk may feel or examine the hops while the kiln fioor is rotating for determining the degree of dryness. This eliminates the necessity of walking through the hops as is usually done in the awkward present-day drying method.

SUMMARY OF OPERATION In the invention method, the hops are delivered from a harvester by the upper conveyor 22 on the belt 29 thereof and from this belt, FIG. 3, the hops pass into the top of delivery chute 37. The carriage 32 and chute are initially positioned centrally of any given kiln 21 as shown in FIG. 2. Due to the described action of the pivoted sensing finger 43 and ratchet bar 42, the carriage 32 and chute 37 will begin a step-by-step forward travel from the center of the kiln toward the side wall 67 thereof to lay down a first even layer of hops on the screen 46. At the end of this movement, the limit switch 85 will operate to cycle the motor 86 one revolution, thereby raising the bar 42 and sensing finger 43 to the height of the next layer of hops. Simultaneously, the carriage motor 34 is reversed and the delivery chute 37 is started in the opposite direction after rising, depositing another layer of hops on the rotating floor. This process continues automatically until the entire batch of hops, layer-by-layer, has entered the kiln.

The drying hot air is allowed to enter the kiln from the duct 81 as soon as the first layer of hops is laid onto the rotating floor and the initial operation of switch 96 sounds an alarm to alert the operator to start the heating and drying cycle. When the final or top layer of hops is laid down, the switch 96 is again operated by the element 94 to sound an audible alarm. If the operator should ignore this alarm, the element 97 stops the entire apparatus by actuation of the switch 98. Normally, the op erator will now advance the carriage 32 to a position as shown in FIG. 2 over the next adjacent kiln so that the filling of the next kiln with hops can commence even before the preceding kiln is fully unloaded.

Rotation of the floor 44 is now stopped and the floor is lowered to the discharge position and rotation is again commenced at increased speed to expel the hops from the floor centrifugally, whereupon the hops slide down through the conical receiver 60 to the underlying conveyor belt 102 leading to the cooling room.

FIGS. 9 to 11 inclusive show a second embodiment of the invention where the overall construction and mode of operation of the apparatus is basically the same as shown and described in the initial embodiment. The only difference in this second form of the invention is that instead of the rotary kiln floor lowering to a discharge position after the drying cycle, the marginal wall of the kiln is elevated from the floor while the floor remains at a constant elevation. Other than for this diiference, the two forms of the invention are identical and only a brief description of the modification is necessary for a proper understanding thereof. In this connection, much of the foregoing detail has been omitted in FIGS. 9 through 11.

In these figures, the rotating floor structure is designated by the numeral 106 and this structure includes a screen or foraminous surface 107 lying on spaced slats which may be constituted by trusses 108, rigidly secured to a center vertical hub or tube 109 turning on low friction bearings 110 at the top and bottom thereof. The bearings 110 are mounted on a vertical post or kingpin 111, rigid with a base plate 112, secured to horizontal framing 113, the latter framing tied into the main uprights 20 of the apparatus. The bottom of tube 109 carries a large bull gear 114, seated on a thrust bearing on the plate 112. A pinion gear 116 driven by a motor 117 imparts rotation to the floor 106 at a fixed elevation. The construction is considerably more compact than the corresponding construction in FIG. 1 where the floor 44 is raised and lowered as well as rotated. Also, the interior of the conical receiver 60 is even less obstructed than in the prior embodiment.

The outer wall 118 of the modified kiln rests upon the floor 106 during the drying operation exactly as described previously and an identical liquid seal 119 is provided exactly as described in connection with FIG. 8. The description of these elements need not be repeated.

In order to discharge the dried hops centrifugally from the floor 106, instead of lowering the floor as previously described, the surrounding Wall 118 is lifted by suitable overhead cylinder-piston units 120 mounted upon the uprights 20. The units 120* have lifting hooks 121 which engage under the baffles 122 of the liquid sealing structure. With the wall 118 thus lifted, the speed of rotation of the floor is increased and the hops are discharged into the conical receiver 60 exactly as previously described. The discharged hops pass from the bottom of the receiver 60 onto the aforementioned conveyor 102.

In the embodiment of FIGS. 9 to 11, the heating air enters the bottom of the kiln from a duct 123 which interconnects with a vertical discharge extension 124 on the receiver 60. A retractable gate structure 125 is provided within the duct and reciprocated by a cylinderpiston unit 126 between closed and opened positions with respect to the outlet 124. A curved bafile plate 127 forms a part of the gate structure 125 and with the gate structure extended as in FIG. 9, the baifie plate 127 directs the hot air upwardly within the kiln toward the foraminous rotating floor 106. When the gate structure 125 is retracted by the unit 126, the outlet extension 124 is fully open so that the dried hops can reach the belt 102.

In all other respects, the construction and operation of the invention in FIGS. 9 through 11 are identical to the prior embodiment.

The invention method of drying hops is much more efiicient than the old manual method and results in much more uniform drying. Automation is achieved to a substantial extent with the saving of much time and labor. The advantages of the invention will be apparent to those skilled in the art without any further description herein.

While the invention has been described throughout in connection with the drying of hops, it should be pointed out that other types of farm products and various solid materials in divided form may be processed or dried by means of the invention and it is not intended to limit the invention to the treatment of hops.

Furthermore, the apparatus is illustrated somewhat diagrammatically for the sake of simplicity and it is desired not to restrict the invention to the precise apparatus components illustrated in the drawings. For example, instead of the described rotary driving means including the motor 50 and associated parts, it may be desirable to have the rotary drive move up and down with the floor and supporting column, in which case there will be provided a suitable torque arm reducer which will move up and down with the column but is prevented from turning by a torque arm anchored to truss member 25 or the like. Additionally, the hydraulic means illustrated in FIG. 7 for supporting the column and raising and lowering it may be varied in design within the scope of the invention. Also, the framing and support structure of the apparatus may be varied considerably.

It is to be understood that the forms of the invention herewith shown and described are to be taken as preferred examples of the same, and that various changes in the shape, size and arrangement of parts may be resorted to, without departing from the spirit of the invention or scope of the subjoined claims.

What is claimed is:

1. A method of drying divided solid material comprising depositing the material in layers on a slowly rotating foraminous substantially horizontal support to gradually build up thereon a thick batch of the material of substantially uniform density, directing heated air upwardly through the rotating foraminous support and through the material over substantially the full area of the support to gradually dry the material, and then increasing the speed of rotation of the support and discharging the dried material from the outer margin of the support by utilizing centrifugal force after completion of the drying cycle.

2. A method of drying divided solid material as defined by claim 1, and confining the material on the rotating support during the material depositing and drying periods with a barrier near the periphery of the support, separating the foraminous support and barrier by relative movement thereof after the drying period, and then increasing the speed of rotation of the support to develop centrifugal force sufficient to discharge the dried material radially from the support.

3. A method of drying divided solid material as defined by claim 2 and the additional step of delivering the centrifugally discharged material to a conveyor and then conveying the material to a remote station.

4. A method of drying divided solid material as defined by claim 1, and wherein each layer of material deposited on the slowly rotating support is in a relatively thin layer laid down on the support by a material discharge device which traverses the rotating support stepby-step in a generally radial path over the support, and

repeating the traversing and laying down of said layers slow speed and subsequently at a more rapid speed, a hops delivery means mounted above said support for laying successive layers of hops onto the support while the same rotates slowly, forced draft means to direct heated air upwardly through the foraminous support and through the hops thereon during said slow rotation and to also prevent any appreciable escape of the heated air in a downward direction or at the margin of the rotary support, and a receiver and conveyor means below said support to receive and carry away the hops when the latter are discharged by centrifugal force from the support due to said subsequent rapid rotation thereof.

7. An apparatus for drying hops as defined by claim 6, and a marginal barrier wall on the rotary foraminous support to confine the hops delivered thereto during the drying cycle, and means to effect vertical separation of said support and barrier wall after completion of hops drying to produce a space between the support and barrier wall through which the hops are discharged radially by centrifugal force.

8. An apparatus for drying hops as defined by claim 7, and wherein said last-named means comprises a central upstanding rotary shaft bodily carrying said rotary support, and axial support means for the shaft operable to raise and lower the shaft with the support.

9. An apparatus for drying hops as defined by claim 8, wherein said drive means for the support comprises a drive motor and gearing having a driving connection with said shaft near the top thereof and also having a sliding connection therewith longitudinally of the shaft, and said axial support means for the shaft including a fluid pressure cylinder-piston device at the bottom of the shaft and lowering the shaft and said support when fluid is exhausted from said device and elevating the shaft and support when fluid is introduced into the device.

10. An apparatus for drying hops as defined by claim 9, and coacting stationary support means engaging and supporting the marginal barrier wall in vertically spaced relation to the rotary support when the latter is lowered.

11. An apparatus for drying hops as defined by claim 10, and wherein said coacting stationary support means includes interfitting baffles on said marginal barrier wall and on an adjacent stationary structural element of the apparatus, said interfitting baffles serving additionally as an air tight liquid seal at the margin of the rotary support, one bafile formed as a receptacle for liquid and the opposing baflle entering the liquid.

12. An apparatus for drying hops as defined by claim 6, and wherein said receiver and conveyor means comprises a conically tapered funnel-like receiver beneath said support to receive dried hops discharged therefrom, and a take-away generally horizontal conveyor at the bottom of the funnel-like receiver.

13. An apparatus for drying hops as defined by claim 12, and wherein the forced draft means includes a duct opening through one side of the funnel-like receiver at an elevation below the rotary foraminous support.

14. An apparatus for drying hops as defined by claim 13, and a valve gate element for the bottom of said funnel-like receiver to close the receiver during the drying cycle and thus prevent the escape of hot air down- Wardly.

15. An apparatus for drying hops as defined by claim 6, and wherein the hops delivery means comprises a generally vertical delivery chute above said rotary support, substantially horizontal guide track means supporting the chute so that the latter may traverse the rotating support, and conveyor means for delivering hops from a remote point into the top of said chute.

16. An apparatus for drying hops as defined by claim 15, and wherein the conveyor means is a substantially horizontal belt conveyor, a carriage for said delivery chute on said guide track means and including an inclined portion terminating near the top of the chute, and said inclined portion of the carriage engaging beneath the 1 l conveyor belt to produce in the belt an inclined delivery portion leading to the top of the chute, the carriage having guide roller means for the belt.

17. An apparatus for drying hops as defined by claim 16, and a drive motor means on the carriage operable to propel the carriage forwardly and rearwardly on said track means.

18. An apparatus for drying hops as defined by claim 17, a vertically movable hops sensing device on the carriage moving therewith and contacting the hops laid down on said rotary support, and drive means for the sensing device operable to elevate the device step-by-step in conjunction with reverse operation of the carriage drive motor means, whereby the carriage and said delivery chute are caused to traverse the rotary support in a generally radial path from a point near the center thereof to a point near the margin of the support repeatedly.

19. An apparatus for drying hops as defined by claim 18, wherein the sensing device comprises a substantially vertical toothed ratchet bar, a pivoted sensing finger on the lower end of said bar engageable with the hops, a switch on said bar operated by movement of the finger and controlling the carriage drive motor means for stepby-step advancement of the carriage and delivery chute, the drive means for the sensing device comprising a drive motor, a lifting pawl reciprocated by the drive motor and engaging the teeth of said bar, and a holding pawl for the bar engaging the teeth thereof and supporting the bar after lifting by the lifting pawl.

20. An apparatus for drying hops as defined by claim 18, and a limit switch mounted near one side of the rotary support, and an actuator element on the carriage engaging the limit switch when the carriage and delivery chute approach the margin of the rotary support to thereby reverse the operation of the carriage drive motor and simultaneously activate said drive means for the sensing device to elevate the sensing device to the next elevation preparatory to laying down the next layer of hops.

21. An apparatus for drying hops as defined by claim 20, and an audible alarm operating switch on the carriage in the path of movement of the sensing device, a first element on the sensing device actuating said switch to sound an alarm when the first layer of hops is laid down to alert an operator to initiate the drying cycle, and a second element on the sensing device near the bottom thereof to actuate said switch and sound the alarm when the final layer of hops has been laid down.

22. An apparatus for drying hops as defined by claim 21, and a safety cut-off switch on the carriage in the path of movement of a projection on the sensing device operable to completely stop the apparatus should the operator not heed the second audible alarm.

23. An apparatus for drying hops as defined by claim 11, and a float operated liquid level control means for said liquid seal on said stationary structural element.

24. An apparatus for drying hops as defined by claim 23, wherein the stationary structural element is a substantially vertical wall surrounding the rotary support in spaced relation thereto.

25. An apparatus for drying hops as defined by claim 6, and wherein said apparatus comprises plural side-byside units in a row, and said hops delivery means comprises an overhead conveyor structure spanning all of the apparatus units in said row and having a power-operated hops delivery chute adapted to deliver hops to the foraminous rotary support of each unit.

26. An apparatus for drying hops as defined by claim 25, and where all of the units of the apparatus including the rotary foraminous supports are circular.

27. An apparatus for drying hops as defined by claim 26, and an overhead inspection catwalk spanning the apparatus units in spaced parallel relationship to the hops delivery means.

28. An apparatus for drying hops as defined by claim 7, and wherein said rotary support comprises a circular substantially flat table structure having a foraminous hops supporting surface, said marginal barrier wall being annular and resting directly on the table structure near the? margin thereof during the slow rotation period of the table, and a central smaller diameter annular wall on the table structure extending thereabove and forming with the marginal wall an annular drying chamber for hops.

29. An apparatus for drying hops as defined by claim 28, and an imperforate section in the table structure inwardly of the central small diameter annular wall to prevent the escape of heat upwardly in the central region of the table structure.

30. An apparatus for drying hops as defined by claim 7, and wherein the last-named means is a means to engage and elevate the marginal barrier Wall from the rotary support while the rotary support remains at a fixed elevation.

References Cited UNITED STATES PATENTS 195,573 9/1877 Chapman et al 34-8 255,564 3/1882 Barclay 34-187 X 554,509 2/1896 Henze 34-187 JOHN J. CAMBY, Primary Examiner U.S. Cl. X.R. 

